Steam-heated piston



R. C. STEVENS.

STEAM HEATED PISTGN.

APPLICATION FILED 050.11. 19w. RENEWED JUNE 1, 1919. r

l ,3 1 2,285 Patented Aug. 5, 1919.

2 SHEETS-SHEET I.

R05; a Siemens Patented Aug. 5, 1919.

Z SHEETSSHEET 2 Roller) C S/er ens' (J M/00mm through said a chamber (in the UNITED STATES PATENT OFFICE.

ROBERT c. srnvnns,

To all whom it may concern:

Be. it known that I, R BERT C. STEVENS, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Steam-Heated Pistons, of which the following is a specification. y i

This invention relates to means for heating the pistons of steam engines, and involves a. construction in which steam is admitted into the interior of a hollow piston from, a source of steam supply, and circulating piston is discharged therefrom, at some, time in its stroke, and may be conducted back to the steamsupply chamber for power purposes. The present construction has the advantage thatthe Water of condensation does not have to be lifted from the lower part of the piston,.but theflow thereof is in the direction of the natural gravity flow. a i i The steam is admitted to the piston from cylinder head which communicates through a hollow tail rod on the piston with the interior of the latter, and the discharge from r the piston takes place through a port in the lower part of the piston wall which. registers at intervalswith an outlet or return pipe; f y

In one form of the invention the outlet pipe opens through the cylinder wall be.- tween spaced rowshof main exhausttports extending around the cylinder,.so that the piston always laps theoutlet passage from the piston, but alternately uncovers the ?respective rows of main exhaust ports, the engine in this case being of the double acting uniflow type. Modificationsare possible enabling the invention to be applied to a unifiow engine having a singlerow of haust ports; and the invention may also be applied to counterflow engines, and no limitation in this respect is imjplied by reason of the fact that the invention is illustrated and described as a uniflow.

In the accompanying. drawings,'

Figure 1 is a longitudinal vertical section of an engine provided with the invention.

Fig. 2 is a cross section on the line .2-2 of Fig. 1. i

Fig. 3'is a section of a modification showing a different manner of supplying steamto the piston.

Fig. 4 is a similar view of another modification.

Specification of Letters Patent.

OF ERIE, PENNSYLVANIA.

STEAM-HEATED PISTON.

Patented Aug. '5, 1919. Application filed December 17, 1917,8eria1 No. 207,572. Renewed June 7, .1919. Serial No.

Fig. is asimilar viewin which only one row of main exhaust ports, is shown.

eferringispecifically to the. drawings, A indicates the cylinder of a. double acting uniflow engine having a. middle exhaust belt Jw'ith which two spaced rows of exhaust ports K communicate. These ports are arranged in rows extending around the cylinder. B is a hollow head which forms a steam chamber containing the inlet valve 13 to the cylinder. C is the the piston rod connected thereto, The piston is hollow, and the piston rod isextended to form, a tail rod D extending through the cylinder head and projecting into a steam chamber G fastened The tail rod D is bored lengthwise as indicated at E and this passage communicates at its inner end through port Fwith the inte rior of the piston. The port H connects the steam space in ber (Land a small port I islocated in the lower part of the chamber f r the purpose of drainage. The tail @rod works through a packing. gland in the cylinder head as shown. y y y Thelower side of the circumferential wall of the pistonis provided near each end with an outlet port M which may be notched to give alonger time for out flow. .One of piston and Dis to. the cylinder head. 1

the head '13 with the chamtheSepOrts M rcgisters attheendof stroke lDI-MCh CllI'BClZIOII with ai port N at the, middle of the cylinder, between the two; rows of main exhaushports K, and theport N connectstoareturn pip'e Piwhich leads to the steam spaceinthe cylinder head B. around1 the piston, outside of the ports M. In the operation of this type,the headB andchamber G contain steam at boiler pres- 1s a draln cock, and .O are packing rings sure, and this steam flows into the interior of the piston through the tail. rod D and port F. At about the endofeach stroke one of the ports M registers with the portN and the steam and water of condensation can flowfrom the interior of the piston through thepipe .P to the berin the head gravity.

bottom of the steam cham- .B, the watenfi owing by By making the ports Hand I rather small, ia slight building up of the W pressure in the chamber G is effected by the displacement of the tail rod when the piston moves toward the right as shown in F 1, and when the piston is in motion the inertia of the water of condensation will tend to throw it at the end of each stroke to the proper end of the piston for its discharge through the port N. That is, when-the piston is in motion the water will flow toward the rear end thereof, in position "to escape through the ports M and N when they register at the end of the stroke. Therefore gravity, inertia and the impulse of the stroke all operate to assista flow of steam at throttle pressure through the piston and out atthe port N and back into the cylinder head, and thus flow may be produced by these 'forces without the'assistance of check valves, consequently thereis an intermittent impulse 'andflow of steam from the steam supply chamber through the piston and back'to the chamber, the water of condensation passing out at the same time.

It should be noted that the ports M are located out of 'line with the ports K, so that they do not register therewith at any time. This is readily 'eii'ectedby locating the ports M in "line with the bridges betweenports "The packing rings'O prevent the escape 'ofa'ny steam from the cylinder to the outlet port N, and' byreason of the location of'the ort N 'betweenthe two'rows of ports K,'t=he torineris'lapped by the piston at all times and the latter are alternately opened and c'losed by' the reeiprocation ot the piston.

Tn the modified form shown in Fig. 3, the tail'rod chamber G, instead of being suppliedwith steam'throu'gh ports such as H, is supplied with steam through a pipe S which'communicates with the main steam supply pipe I, the pipe S having a bell mouth It presented toward the direction of flow in the stream pipe, whereby, at each jrush'o-f steam incident'tothe opening of the inlet valve B, an impulse of steam is produced through the'pipe S and into the chamber 'G and continuing through the piston Whichtit that time is at the dead center with theportsM andN in register.

' In the modification shown in Fig. 4, a check valve V is provided at the port H,

"and a'eheck valve U at the port-N, and these check valves will assist theflow through the piston, because when thetail rod 1) travels to therightthe check valve V will close because of the increased pressure in thechamber G, giving a pumping action'w hich will ifo'rce a 'flowthrough'the "piston and through the valve U which is thereby opened.

In the modification shown in Fig. 5 the valves V and U are also used, but instead of a double row of ports K a single row only is provided, and only'one port M which registers with the port N at the end of eacn stroke inone direction, but not in the other direction. There is no danger that, in this form, the valve U will be opened when it is uncovered by the piston, because the pressure in the cylinder will then be much less than the pressure on the other side of the valve U communicated from the hollow head through the pipe P.

I claim:

1. The combination with a steam engine cylinder and a hollow piston therein, of a steam chamber on the cylinder head, a hollow tail-rod projecting from the piston and commun'icatiing'with the interior thereof and working through the cylinder head into said chamber, and a return pipe communicating with said chamber and having a port in the cylinder wall, the piston "wall having a port which registers with said port'at a certain time during thestroke ol the piston, to permit outflow from the piston to said pipe.

port in the piston registers at about theend ot' the compression stroke of the piston.

3. The combination with asteam engine cylinder having a steam supply passage thereto, and a hollow piston in the cylinder, of a steam chamber on the cylinder head communicating with said passage, a hollow tail rod projecting {from the piston, through the cylinder head and into said chamber,

said'piston-havinga port in the wal'lthcreof, and a return pipe communicating at one end with said supply passage-and having a port at the'other end into the cylinder and with which the port in the piston registers at about the end of the compression stroke of-the piston.

In testimony whereof, I afiix my signaturein presence of two witnesses.

ROBERT C. STEVENS.

Witnesses H. E. (3013mm, E. G. FRANZ.

Copies of this'patent 'may be obtained for five cents each, by addressing the Commissioner of ratents,

' Washington, D. G. 

